Viewing Stereographs in 3D
The start of the American Civil War in 1861 coincided with a surge in stereo photography--a technique that renders photos in three-dimensional depth. A pair of similar images combines into a single 3-D scene using a special viewer. (Or, you can "freeview" by crossing your eyes!)
How Can I See the 3-D Effect?
Digital anaglyphs are one tool. Two color-filtered images are overlaid to create the depth illusion when viewed through glasses with complementary color lenses, often red and cyan.
Matt Raymond is donating sample anaglyphs to the Library of Congress to help us take the first step in unlocking the full 3-D effect available through historic stereographs.
Bob Zeller led the way by opening the world of Civil War stereographs to new generations, beginning with two books in 1997 and 2001. Sample anaglyphs are at the Center for Civil War Photography External site.
Typically, a camera with two lenses exposed side-by-side images onto a single glass plate negative. Look closely at these tent tops to see the slightly different angle captured by each lens.
In the raw, uncut negative, the image on the right shows what your left eye would see--more of the tent is visible to the left of the ladder. (Note: Image from uncut negatives are displayed with positive polarity for legibility's sake.)
To create a print for 3-D viewing, the images from uncut negatives had to be switched, cropped, printed, and pasted on card stock at a distance similar to the space between your eyes. The finished cards are usually 3.5 x 7 inches.
Where Can You See More Civil War Stereos? Or, Make Your Own 3-D Views?
Most of the Civil War stereograph glass plate negatives in Library of Congress collections were long ago separated into two parts. They are the easiest source to work with, if you'd like to try your own hand at creating 3-D images. Almost 1,500 pairs of separated negatives are online [view separated stereograph glass plates]. Almost 700 uncut stereo plates are also online, if you have more time to crop and switch halves as well as align the parts digitally. [View uncut stereograph glass plates]. Wikipedia external links and other sites offer instructions for making digital anaglyphs. Reminder: For digital 3D viewing from these uncut negatives, switch the left and right images to match what your eyes would naturally see.
Alternatively, you can tap the digitized stereo cards as a source.
3-D Viewing Devices
Many kinds of viewers for physical cards are available. For an illustrated summary, see:
- Central Pacific Railroad Photographic History Museum
http://cprr.org/Museum/Ephemera/Stereo-Viewers.html external links
http://stereographer.com/viewers.html external links.
Inexpensive glasses for viewing stereographs, including red/cyan paper frames for viewing anaglyps, are available from the following vendors:
- 3Dstereo.com, Inc.
http://www.3dstereo.com/viewmaster/tig.html external links
- Berezin Stereo Photography Products
http://www.berezin.com/3d/3dglasses.htm external links
Stereo Print Viewer and Deluxe Stereo print view work the best with the Library's online images.
Plastic Stereo Card Viewer can be used with the Library's online images.